This invention relates to electrical counters and to equipment including such counters.
In many applications it is desirable to maintain a count, such as of the number of times equipment has been operated. It can also be desirable to store information about the operation of that equipment in the counter, such as may be indicative of a fault in its operation.
Various electrical stores are available which can maintain such a count and store a fault code or the like. Most of these stores, however, are relatively expensive. At least one form of low cost store is, however, available in the form of an electrically-erasable programmable read only memory (EEPROM). Currently available EEPROM's, however, suffer from the disadvantage that the action of writing into the store deteriorates the device. This limits reliable operation to about 10,000 write cycles for each register in the store. Where the EEPROM is used to store both counter information and fault status data or the like, at least two write operations are required each cycle, thereby limiting use of the store to about 5000 operations.